If it ________ for the heavy rain, we ________ the Songshan Mountains yesterday.

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A．were not; could have climbed

B．were not; could climb

C．had not been; could have climbed

D．had not been; could climb

Taking his advice will ________ you a lot of trouble.

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Tom sat in class, with his eyes ________ on the flowers out side the window.

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The president ________ a speech at the national conference.

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I still remember ________ to Shanghai at the age of seven.

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News reporters must find out important information ________ possible.

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When I entered the room, I saw a stranger ________ in my place.

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Would you mind ________ alone at home?

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My son set out ________ question when I set about ________ lessons.

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—You were brave enough to raise objections at the meeting.

—Well, now I regret ________ that.

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